Center-clip release for printing cylinders



June 3 i 1924.

T. s HANNAFORD CENTER CLIP RELEASE. FOR PRINTING CYLINDERS Filed May 4, 1923 Patented June 3, 1924.

UNITED, STATES THOMAS S. HANNAFORD, OF WINTHROP, .MASSACI-IUSETTS, ASSIGNOR 0F ONE-HALF TO PATENT OFFICE.

FREDERICK O. YOUNG, .OF NEWTON, MASSACHUSETTS.

CENTER-CLIP REL-EASEFOR- PRINTING CYLINDERS.

Application filed May 4,

To all whom it may concern.

Be it known that I, THOMAS S. HANNA- FORD, a citizen ofthe United States, residing at l/Vinthrop, in the county of Suffolk and State of Massachusetts,have invented new and useful Improvements in Center-Clip Releases for Printing'Oylinderaof which the following is a specification.

The present invention relates to rotary and web printing presses and is particularly concerned with the printing or plate cylinders of such presses. Specifically it is an adjunct to the center clips used between adjacent stereotype printing plates for securing them to the cylinder.

The object of the invention is to furnish a means which will automatically free the center clips fromthe plates when the end clips are loosened, and thereby avoid the need of hammering and incidentally damagingthe center clips in order to loosen-them.

In the rotary and web printing presses with which this type of clip is used, the printing or plate cylinder is made with a length suflicient to take four stereotype plates in longitudinal alinement, and two plates in circumferential arrangement. These plates may be considered, with respect to their longitudinal order, as comprising two outer or end plates and two inner or middle plates. The two inner plates .abut at their inner edges against a rigid fixed rib at the middle of the cylinder which has lips adapted to overlie the beveled inner edges of the cylinder.

the plates. Between each inner plate and the adjacent outer plate .are intermediate clips which are called center clips and are adapted to overlap and engage both adjacent plates. These center clips are necessarily movable longitudinally of the cylinder in order to engage and release the inner plate. Finally at the ends of the cylinder arethe end clips which overlap the beveled outer edges of the .end plates. When these end clips are screwed home they press against the end plate, crowding the latter against the center clips and said clips against the inner plate, and finally crowding the'inner plate against the stationary central rib of men the plates are to be removed, the end clips are backed off,.leavingjthe. outer plates free to be .removedand relieving the binding or crowding pressure on the center clips.

But with the center clips as'heretofore 1923. Serial No. 636,583.

made and used, difliculty is met with in clearing them from the inner plates because the soft nature of the metal alloy of which the plates are made causes the clips to be embedded in them more or less and to stick and resist disengagement, even after the clamping pressure of the outer clips and plates has been relieved. The easiest and quickest way,- then, to free the center clip is to pound it with a wrench, which the pressman already has in hand for other purposes. This causes the clips, which are made of mild steel, to be more or less deformed.

In the brief time which frequently is all that can be allowed for. changing plates in a newspaper press room, under the hurried conditions obtaining when an edition must be gotten out at a certain time, the pressmen are not able to use as much care in loosening the clips as they could if more time were at theirdisposal. The result is that the clips are rapidly knocked out of shape. Their outer edges particularly are offset and deformed so that the clips no longer conform accurately in surface contour with the edge of the plate which they are to engage. Thus the trouble due to the clip indenting the inner plate and sticking to it is increased, causing more difficulty in releasing it and requiring harder and more prolonged hammering for that purpose, and causing still greaterdeformation which still further increases the difiiculty.

When the clips are so far deformed that they will not properly hold the plates, they must be removed from the cylinder and is set by hammering between dies which restores their original form; but after the resetting operation has been performed a few times on a clip the holding part begins to crack and separate from the body part. Vhen this happens the clip is useless and must be discarded.

My invention has for its object to enable the center clips to become automatically disengaged from the inner plate when the outer plate is loosened and removed, and thereby to avoid the need of hammering the benter clip to free it from the inner plate and consequently to remove the limitations heretofore existing to theuseful life of the clip. The. means for accomplishing this object and the combination thereofwith the center clip and plate cylinder, together with the principles embodied in such means and all equivalents thereof, constitute the invention which I here claim and desire to protect. The preferred embodiment of my invention and one of the possible modifications thereof are illustrated in the accompanying drawings and described in detail in the following specification.

In the drawings,

Figure 1 is an elevation of a plate cylinder or printing cylinder of a rotary web press carrying four plates in longitudinal alinement and illustrating the plate holding means. 7

Figure 2 is a similar view on a larger scale showing one end of the cylinder only and illustrating my invention.

Figure 3 is a longitudinal section of the cylinder on line 33 of Figure 2.

Figure 4 is an end view of the cylinder with parts broken away and shown in section.

Figure 5 is a fragmentary sectional view of the guideway in which the center clip is mounted.

Figure 6 is a perspective view of the center clip detached and the preferred form of the means which I have devised for freeing it from the printing plate.

Figure 7 is a sectional view of the releasing device in detail.

Like reference characters designate the same parts wherever they occur in all the figures.

The numeral 1 represents the plate cylinder as a whole, which may be considered as typical. of the corresponding cylinder provided with any rotary or web press. 2, 2 are the inner printing plates and 3, 3 the outer printing plates, these being typical stereotype plates which are curved to fit the circumference of the cylinder and have beveled edges 4 to underlie the clips and equivalent holding means. 5 represents the trunnions or journals of the cylinder by which it is mounted in the journal bearings of the printing press.

The two inner plates abut against a central rib 6, which is an integral part. or at least a permanent and immovable part, of the cylinder and is of substantially dovetail section having lips which overlap the adjacent beveled edges of the inner plates.

Between the inner and outer plates are clips 7 which are called center clips; and adjacent to the outer edges of the outer plates are the end clips 8. The center clips are mounted to travel on guides 9, 9 formed at the opposite sides of recesses 10 which are formed in the cylinder. The clip 7 is made with a body portion 7 having grooves T which receive the guides 9', and flanges 7 which underlie said guides. The outer surface of the body portion-is flush with the surface of the cylinder, while the plate holding portion or clip proper is a rib formed on the top of the body and having undercut opposite edges which overlap the adjacent edges of the inner and outer plates. One end 10 of the recess in the cylinder is made large enough to receive the body of the clip when the latter is clear of the guides 9, whereby the clip can be put in place and removed. An adjustable stop screw 11 threaded into a hole in the clip and provided with a lock nut 12 isprovided to prevent the clip from accidentally moving clear of the ways and falling out of place.

The end clips 8 are similarly mounted in guideways in the end of the cylinder and are engaged with screws 13 which are confined against endwise movement in bearings 14, whereby they are adapted, when rotated, to force the end clips against the adjacent plate, or to withdraw them. When the end clips are forced against the outer plate, they crowd the latteragainst the center clips, in turn crowding the center clips against the inner plate and forcing the inner plate against the middle rib. The tightening of each set of end clips thus secures two plates. But loosening of the end clips has heretofore not had the effect of releasing the inner plate as well as the outer plate on account of the tendency of the center clip to embed and stick to the inner plate as previously described. Hence, although with the clips heretofore used it has been easy to remove the outer plate, removal of the inner plate has been diflicult, and accomplished only after hammering the center clip free.

I have by this invention provided spring means which are applied against the center clip from the side thereof which bears on the inner plate. Such spring means are arranged to be put under compression when the plates are clamped and are constantly operating on the center clips to free them from the inner plate when the pressure applied through the outer plate is removed.

The preferred form of spring means consists of two blocks 15 and 16 which are adapted to slide on the guides 9, 9 in the same way that the center clip itself is arranged to slide, and springs 17, 18 interposed between these blocks. There is also a screw 19 which limits the separation of the blocks and is threaded into one of them while its head occupies a hole in the other and is arranged to abut against a shoulder 20 at the bottom of said hole. These springactuated blocks are mounted in the recess 10 at the side of the center clip toward the middle of the cylinder and the block 16, the block more remote from the clip, is made fast in the recess by a set-screw 21 which is mounted in the block and is set up against the bottom of the recess. The block can thus be shifted and adjusted to various positions and, according to its position, the

force which the spring exerts on the clip may be varied. In any adjustment, of course, the springs exert force against the clip when the latter is in the position for holding the inner plate.

By virtue of this adjustment, the springs are put under tension when the clip is moved, by pressure exerted through the outer plate, into its gripping relation to the inner plate. The springs then continue to exert force tending to release the clip and have the function and effect of instantly displacing the clip as soon as the outer plate has been taken off, leaving the outer edge of the inner plate free so that it can be raised from the cylinder and the whole plate readily taken off.

It is to be understood, of course, that the combined force of all the springs acting on all the clips which hold a single plate is not great enough to oppose any substantial force against the tightening up of the clips to hold all the plates securely; although the springs are sufficiently powerful to free the clip on which they respectively act, even though such clip should have been somewhat embedded into the material of the printing plate.

An important practical advantage of the abutment blocks which I have here disclosed is that they can be applied to existing printing plates without any modification whatever in the structure of any parts of the press and without the need even of drilling a hole. In applying the blocks it is necessary only to assemble them together with the springs and coupling screw and then place them in a recess and engage them with the guides in the same way that the clip itself is so placed and engaged.

The springs here described are typical of any resilient means which may be used in this or any equivalent combination for the purpose set forth; and the claims are to be construed accordingly and without limitation to the specific springs and arrangement shown, except as required by the context.

What I claim and desire to secure by Letters Patent is:

1. A printing press, a cylinder adapted to support printing plates and having a longitudinal recess, a center ,clip mounted to slide in a guided path in said recess, an abutment block mounted and adapted to be made fast in said recess, and being adjustable along said path, and a spring interposed between said abutment block and the center clip and adapted to exert force on the clip opposing movement of the latter in one direction in said path and tending to move it in the opposite direction.

2. In a printing press, a printing plate cylinder having a longitudinal guideway for the center clip, a center clip occupying said guidewuy and caused thereby to move in a prescribed path, blocks fitting said guideway at one side of the center clip and springs confined between said blocks adapted to react against one of them and to press the other against the clip, the block against which said springs react having means for adjustably clamping it in the guideway for adjusting the pressure exerted by the springs when the clip is in a certain position.

3. A device for releasing the center clips of plate cylinders for printing presses comprising complemental blocks adapted to be placed in the recess and engaged with the guides with which'pl-ate cylinders are provided for holding a center clip, and springs interposed between said blocks, one of the blocks having means for securing it against movement with respect to said guides.

at. A releasingdevice for a center clip of the plate cylinder of a printing press consisting of two blocks, both adapted to be placed in the center-clip holding guideway of such cylinder beneath and clear of the inner printing plate on the cylinder springs interposed between said blocks, and a stop coupling arranged and constructed to limit the separation of said blocks from one another while permitting movement of approach between them by the stress of said springs, said blocks having guiding portions interengageable with the guides which are provided in printing plate cylinders for the reception of the center clips of said cylinder.

5. In a printing press, a cylinder adapted to support printing plates and having a longitudinal recess, a center clip mounted to slide in a guided path in said recess, an abutment block mounted in said recess and being adjustable along said Path, a spring interposed between said abutment block and the center clip and adapted to exert force on the clip opposing movement of the latter in one direction in said path and tending to move it in the opposite direction, and means for securing said blocks at a desired location with relation to the range of movement of the clip.

6. In a printing press, the combination with the printing plate cylinder and a center clip mounted to engage the adjacent edges of inner and outer printing plates, of an abutment at the side of the clip toward the inner one of said plates adapted to be secured adjustably to the cylinder, and spring means arranged to react against said abutment and to apply force to the clip away from said inner plate.

In testimony whereof I have affixed my signature.

THOMAS S. HANNAFORD. 

